I made a three tiered anniversary cake a couple of years ago in June (it was thirty five degrees) and coverered it in a buttercream similiar to the mouselline.  I made flat fondant flowers and then pushed the centre in to give a bit of dimension.  I decorated it the night before and put it in the fridge and took it out in the morning.  It held up the whole day. Not a single flower moved.  I attached a picture so that you can see the type of flowers (don’t judge my ribbon, I have gotten better!).  I am not sure how detailed your flowers will be so I would think that if they aren’t too heavy they will stay.

moderncake - 21 April 2011 11:39 PM

I made a three tiered anniversary cake a couple of years ago in June (it was thirty five degrees).

I assume you mean 35 Celsius, 95 F.

Rose, try using chocolate modeling, it is waterproof.  we applied them on cakes frosted with whipped cream all the time at the bakery, refrigerate them for day, etc, etc, no smearing.

/H

Rose, try using gum paste and put it right after you assemble the cake at the reception.

what kind of “small fondant flowers are you making? Because that will have a bearing on whether or not the buttercream will affect them on a bad way if attached ahead of time. Also if you mix a little gumpaste w/ your fondant it will help it hold up a little better if you are making flowers with depth such as roses or lilys. Hope this helps

Use edible glue to attach them. That’s what we use all the time.